Electricty 1-7 Ch 4

Question 1

In a purely inductive circuit, the _______ leads the _______ by 90°.

Answer 1

Applied voltage
Current

Question 2

In a purely capacitive circuit, the _______ leads the _______ by 90°

Answer 2

Current
Applied voltage

Question 3

Quantities that have only magnitude are called _______. Those that have magnitude and direction are called _______.

Answer 3

Scalars
Vectors

Question 4

The length of the line is proportional to the _______ of the vector quantity.

Answer 4

Magnitude

Question 5

What is it called when vectors are added or subtracted?

Answer 5

Resultant Vector or
Resultant

Question 6

Two vectors that are 90° apart can be added graphically using the what?

Answer 6

Vector triangle method

Question 7

A right triangle is one that contains a ___ angle?

Answer 7

90°

Question 8

The side of the triangle opposite of the 90° angle is called the _______.

Answer 8

Hypotenuse

Question 9

The length of three sides of a right triangle are related by the what?

Answer 9

Pythagorean theorem

Question 10

The two angles of a right triangle smaller than 90° are related to the lengths of the sides by the trigonometric relationships of ______, _______, and _______.

Answer 10

Sine
Cosine
Tangent

Question 11

Once the value of sine, cosine, and tangent of an angle is known the size of the _______ in degrees can be found in standard tables of trigonometric functions.

Answer 11

Angle

Question 12

_______ _______ are used to describe the time relationships between AC voltages and currents.

Answer 12

Phase angles

Question 13

A waveform shows all of the __________ values of current or voltage throughout the complete sine-wave cycle

Answer 13

Instantaneous

Question 14

Current flowing at every point in an RL circuit is the ______.

Answer 14

Same

Question 15

The relationship between the applied voltage and the voltage drops in a series RL circuit is such that the applied voltage equals _______ _______ of the voltage drops.

Answer 15

Vector sum

Question 16

The current in a RL series circuit is the _______ at _______ point.

Answer 16

Same
Every

Question 17

In resistive circuits, all of the power delivered by the source is __________ by the load.

Answer 17

Dissipated

Question 18

What graph is made to show circuit impedance changes with frequency?

Answer 18

Frequency response curve (of the circuit)

Question 19

The merit rating (or Q) of a coil is determined by calculating the ratio of inductive _______ to _______.

Answer 19

Reactance
Resistance

Question 20

In a parallel RL circuit, the resistance and inductance are connected in parallel across a voltage source such a circuit thus has a _______ branch and an _______ branch.

Answer 20

Resistive
Inductive

Question 21

In parallel RL circuits, _______ is the common quantity.

Answer 21

Voltage

Question 22

As the frequency _______, the impedance comes closer and closer to the value of the resistance.

Answer 22

Increases

Question 23

Any parallel RC circuit, each branch voltage is _______ as the applied voltage

Answer 23

The same

Question 24

When calculating impedance, two vector quantities cannot be added directly; _______ _______ must be used.

Answer 24

Vector addition

Question 25

The current through each branch of a parallel RC circuit is _______ of the current through the other branches

Answer 25

Independent

Question 26

The frequency of which the net reactance to zero, or were Xl equals Xc, is known as the _______ _______

Answer 26

Resonant frequency

Question 27

The impedance of a series LCR circuit is _______ at resonance, so the current must, therefore, be _______

Answer 27

Minimum Maximum

Question 28

When branch voltages and source voltages are in phase, the voltage is used as the _______-_______ phase reference, and the phases of the other circuit quantities are expressed in relation to the _______.

Answer 28

Zero-degree Voltage

Question 29

The line currently in parallel LCR circuit is equal to the _______ of the three branches

Answer 29

Vector sum

Question 30

To determine the impedance of a parallel LCR circuit, you must first find _______ of the inductive and capacitive branches.

Answer 30

Reactance (X)

Question 31

Frequency changes towards the resonant frequency cause an _______ in impedance. Frequency changes away from the resonant frequency cause a _______ in impedance.

Answer 31

Increase Decrease

Question 32

The impedance of a parallel LCR circuit is found by finding the ________ of the L and C branches, and combining it ________ with R.

Answer 32

Net reactance Vectorially

Question 33

At resonance, an ideal parallel resonant circuit has ________ line current and ________ impedance.

Answer 33

Zero Infinite

Question 34

At resonance, the line current in a practical parallel resonant circuit is ___-_______ with the applied voltage

Answer 34

In-phase

Question 35

The term filter means to offer large ________ to, or ________ , voltages and current of certain frequencies

Answer 35

Opposition Reject

Question 36

Transformers are often used to match the ________ of a source to that of a load

Answer 36

Impedance